UE4 foliage lighting bake issue

So I’m trying to bake lighting in my scene, I have a grass field, nothing too odd. My grass has light-maps. When I bake my lighting, grass is relatively unaffected by the lighting. Also on top of this when I bake my lighting, the lightmap size changes after it’s baked. It’s gree when I press alt +0 beforehand, and after it’s dark blue. I have no idea what’s happening. I tried reimporting my grass, tried overriding lightmaps, tried a lot of things. The grass is painted on with foliage. Don’t know how to fix this.